The caterpillar chromatin pattern of the nucleus in longitudinal section an
d owl-eye appearance in transverse section characterize the Anitschkow cell
of Aschoff bodies in rheumatic heart disease. Determining whether it is of
muscle origin or cardiac histiocyte has been a source of controversy for m
any years. In a study of fetal and neonatal hearts from humans, vesicular n
uclei often displaying the Anitschkow chromatin pattern were the predominan
t cell type in the myocardium. Because a similar pattern was also observed
in two cell types related to laryngeal cartilage and the neighbouring fibro
us tissue in a six week old neonate, it was concluded that the Anitschkow c
hromatin pattern probably indicates cellular immaturity rather than any spe
cific cell type.